Add initial styles for daterange markup
Don't import ; update less buildfile and css file
Don't import `.input-append .add-on`; update less buildfile and css file
Implement initial daterange picker
Merge latest master changes into range branch

--HG--
rename : build.less => build/build.less
Merge latest master into range branch
Merge latest master changes into range branch
Bind to events only when the picker is shown.

Greatly increases performance on slow machines with IE8 when multiple
datepickers have been instantiated.
Fixes a memory leak.
Differentiate between main events (needed at picker init) and secondary events (only needed when picker is open)
Build event handler lists at init, not every time we attachEvents
Fix range class names reversion
Update functions used to update picker values
Fix off-by-one error
Merge latest master into range branch
Add remove option for range picker
Add inputs option, for explicitly-created rangepickers
Style in-range today cells nicely
Merge range branch into master